German Patent Application No. DE 10 2014 200 494 A1 describes a method for operating a vehicle, first trajectory parameters for calculating a target trajectory of the vehicle being ascertained depending on an estimated friction value; the estimated friction value being an indication of a friction between a wheel of the vehicle and a roadway on which the wheel is rolling; depending on the at least one parameter, either the target trajectory of the vehicle being calculated depending on the first trajectory parameters, or second trajectory parameters being ascertained depending on a new friction value that is less than the estimated friction value.